Please review this shower pan install. Did I pay a lot of $$ for subpar work?

I've been arguing with my plumbers for 2 days. So I'm sending pictures of the 32x60" shower pan install for an outside opinion.

The plumbers said they had to use shims to level the pan because the subfloor was so out of level. They used some trim pieces I have from a previous job. I questioned the job but they insisted they knew what they are doing. I called owner of company and he sent the two plumbers back out and they told me they put thinset in the middle of the pan and the trim was used because the subfloor was so out of level. They said if I wanted them to reinstall the shower pan, I'd need my carpenter to level the subfloor first. After they left, I crawled around on the floor to check their work closer.

It appears the plumbers have put 5/8" trim pieces all around the shower pan -- under both the drain end and the far end (see pics). I am not sure why they did this. I checked level of the subfloor in the 32" direction and the 60" direction and both appear to be near level (see pics). The subfloor is no where near as off-level as indicated by the plumber's use of 5/8" trim pieces being used as shims.

In addition, I checked the pan itself. It appears to have a "hump" in the middle of it (see photos). Is this normal? It may be the way the pan is manufactured or the thinset in the middle of the pan may be the cause for the hump or the drain may be too high -- I am not sure.

Please look at the pictures of this shower pan install and give me your opinion. I paid professional plumbers a lot of $$ installing this.

Thank you,
Cubgirl

P.S. Not all the pictures uploaded (threre are 9). I will add 2nd thread with the 4 missing pictures. Thanks again.

Without reading the installation instructions, it's hard to say. But, I will comment that most pans call for them to be installed on a level floor, with 100% contact. If yours does, then no, it is not installed properly. It must be solid with no flex, or it will eventually crack and leak.

We pulled it up and there was still wet compound in the middle underneath (two weeks after install) just in spots. Not sure what it was but it wasn't sandy mortar - more like joint compound. This also meant that the trim pieces on the sides were weight bearing. This is a no-no.

My OTHER plumber (who I've used before but he was on vacation during this install) is going to reinstall the shower pan with mortar to level it on the floor. It needs to be in full contact with floor, not raised up with make-shift shims like the old guys did it.

BTW: I squawked so much, I got my money back without even asking for it.